Fishing tools for oil wells



Sept. 20, 1955 H. PRlGE FISHING TOOLS FOR OILWELLS Filed May ll, 1955 IN VEN TOR. Henry price BY A free/Vey United States Patent O FISHING TOOLS FOR OIL WELLS Henry Price, Denver, Colo., assigner to `lohn L. Weber, Denver, Colo.

Application May 11, 1953, Serial No. 354,282

2 Claims. (Cl. 294-102) This invention relates to improvements in devices for retrieving drilling tools from deep wells which devices are generally referred to as fishing tools.

In the operation of drilling deep water and oil wells it sometimes happens that the drill shaft breaks and since the break occurs at a considerable depth it requires specially constructed tools for grappling the broken part and raising it to the surface. Many differently constructed tools for this purpose have been invented and are in fuse.

It is the object of this invention to produce a simple but highly reliable device or tool for the purpose pointed out, which can be manufactured and sold or leased at a reasonable price.

Having thus set out the principal object of the invention the construction and the manner in which it is used will now be described for which purpose reference will be had to the accompanying drawing in which the device has been illustrated and in which:

Figure 1 is a diametrical section taken on line 1-1 Fig. 3 and shows the parts in normal or inoperative position;

Figure 2 is a diametrical section taken on line 2-2 Fig. 4 and shows the relation of the parts after the device has attained an operative position on the broken off drill rod.

Figure 3 is a section taken on line 3 3, Fig. 2;

Figure 4 is a section taken on line 4-4, Fig. 2; and

Figure 5 is a section taken on line 5 5, Fig. 4.

Referring now to the drawing reference numeral represents the casing which varies in diameter from 4 to l() inches or more but which is usually 8 inches in diameter in ordinary oil wells. The part designated by 11 is the upper end of the broken drill rod which for the purpose of illustration will be assumed to have a diameter of 4 inches. The top 12 will be assumed as having been broken, leaving the string below the break in the well. against the inner surface of casing 9 as shown by broken lines.

The tool to which this invention relates is shown directly above 11 in Fig. 1 and is coupled in the .usual manner to the lower end of drill rod 13. The lower end of the tool is formed by a steel ring 14 whose outer diameter is slightly less than the inside diameter of the casing. Ring 14 has an outwardly flaring inner surface 15 for a purpose which will presently appear.

Four identical rectangular steel bars 16 have their lower ends welded to the inner surface of ring 14; the lower ends of the bars are beveled as indicated at 17. The upper ends 18 of bars 16 are welded to the lower end of part 19 which has been shown as having the same diameter as drill rod 11. Bars 16 flare outwardly in an upward direction, from ring 14 and attain their widest spread at point 20 somewhat above the middle point between 14 and 19. Slidable freely on that portion of each bar below point 20 is a steel jaw 21 whose inner surface is transversely concave as shown in Figure 4 and provided with a plurality of teeth 22. These jaws are as massive as practical to assure a suicient force tend- Sometimes 11 leans towards and even rests I 2,718,427 Patented Sept. 20, 1955 ICC ing to move them downwardly to avoid the necessity of employing springs which might otherwise have to be used.

Let us now assume that the drill bar has broken leaving the lower portion 11, which may stand centrally as shown in full lines or lean to one side as shown in Figure 1. The fishing tool which has been described above is now lowered carefully and slowly until it telescopes over the upper end of part 11. The outwardly flared surface 15 helps to direct the upper end of 11 into the device. As the tool is lowered jaws 21 will be pushed upwardly until the drill rod 11 slips between them until its upper end abuts the lower end of part 19. The tool is now moved upwardly but the jaws cut into the outer surface of rod 11 and since the bars 16 taper inwardly in a downward direction it is evident that a point is soon arrived at where no further downward movement of the jaws can take place and the part 11 can then be raised.

Since the parts must be designed and sized to t both the casing and the diameter of the drill rod it is evident that a separate tool must be designed for each of the several sizes of casings. In most cases each well driller employs the same size of casing and drill rod, therefore it is seldom that an assortment of sizes must be carried, but since the tool is comparatively inexpensive the matter is of little importance.

The ends of bars 16 are welded to ring 14 and plug 19 and may be provided with any desirable means to assure that the parts will not separate during use. Rods 16 have been shown as rectangular because in such close spaces such a cross section will provide" greater rigidity per unit area available than any other.

What is claimed as new is:

l. A device for grappling and removing broken drill rods and the like from wells having a casing, comprising, a steel ring of an outside diameter somewhat smaller than the casing in which the broken drill rod is positioned, a cylindrical block of substantially the same diameter as that of the drill rod to be grappled and removed, four bars of rectangular cross section interconnecting the inner surface of said ring with the outer surface of said block, said bars being spaced substantially degrees apart, the lower and the upper ends of the bars being welded respectively to the inner surface of the ring and the outer surface of the block, each bar comprising two straight angularly related sections, the bars being so positioned that the vertex of the angle projects outwardly, the greatest distance between the outer surfaces of the bars being no greater than the outside diameter of the ring, and a jaw member having a rectangular opening, slidable on that portion of each bar between the top of said ring and the vertex of the angle between the two sections of the bars, the inner surfaces being provided with a plurality of teeth for effecting an engagement with the drill rod to be removed, the lower edge of said ring having its inner surface beveled to facilitate its telescoping over the drill bar to be removed, the distance between the inner surfaces of the jaws when in their lowermost position being less than the diameter of the drill bar to be removed and the corresponding distance when the jaws are at their uppermost position being greater than the diameter of the drill rod.

2. A device in accordance with' claim 1 in which the inner jaw surfaces are concave.

References Cited in the file of this patent UNITED STATES PATENTS 358,132 Uhler Feb. 22, 1887 1,376,014 Ginter Apr. 26, 1921 1,388,992 Dutton Aug. 30, 1921 1,707,085 Krueger Mar. 26, 1929 2,661,978 Lauro Dec. 8, 1953 

